Electrical conductor



May 5 w T BARRANS ETAL ELECTRICAL CONDUCTOR Filed March 3, 1939 2Sheets-Sheet 2 F IG. 4

W 7. BARRANS INVENTORS. R M COL 5 Karma EV Patented May 5, 19422,281,542 ELECTRICAL CONDUCTOR William T. Bari-ans, Towson, and Paul M.Cole, Dundalk, Md., assignors to Western Electric Company, Incorporated,New York, N. Y., a corporation of New York Application March 3, 1939,Serial No. 259,508

15 Claims.

This invention relates to an electrical conductor and more particularlyto an electrical conductor of the retractile extensible type.

An object of the invention is to provide an efiective and compactretractile cord.

In accordance with oneembodiment of the invention three conductors areenclosed in a braided covering to form a coiled cord, the outerconductor being of greater length than the inner conductors and thetension in the strands form'- ing the braid being so proportioned as toprovide a natural twist-in the conductor.

A complete understanding of, the invention may be had by reference tothe following description taken in conjunction with the accompanyingdrawings, in which-- Fig. 1 is a front elevation of a machine for makingthe conductor of this invention;

Fig. 2? is an enlarged fragmentary sectional plan View taken on the line22 of Fig. 1;

Fig. 3 is a sectional view taken on line 3-3 of Fig. 2;

' embodying the invention.

Referring now more in detail to the drawings, a braider is shown in Fig.1 having a frame 6. The braider has a rotating braider head carrying aseries of cops I of yarn rotating in a counterclockwise direction and asecond series of-cops 9 rotating in a clockwise direction looking at themachine from above.

The details of the mechanism of this machine are more fully disclosed inthe patent to Miller, 1,602,442 of October 12, 1926, and will not bedescribed herein.

A plurality of conductors 9, to be covered with braiding, pass upwardlythrough the braider head. The upper portion H of the braider head isstationary and has a cross piece 12 provided with a Y-shaped fork I 3and a cut out portion l4 forming triangularly spaced guides for thethree conductors. also a guide IS, the guiding portion of which isU-shaped. From the position shown in Figure 2 the conductors and braidedcovering rotate 90 in a clockwise direction before reaching the capstanI9 and the upper portion of the guide I5 is twisted so as tosubstantially follow the twist in one of the conductors. The twistthusplaced in the cord assists in the helical coiling of the cord. As theyarn i6 is interbraided on the conductors it contacts with two of theconductors but is prevented from contacting the third conductor by theguide i5 until it is close to an axial delivery take-up capstan I9. Inpassing over the capstan the two inner conductors lie Attached to thecross piece is y .substantially against the outer periphery of thecapstan and the third conductor lies radially outwithin the braid. Sincethe outer of the three conductors is of a greater length than the innerconductors it therefore has a natural tendency to form a helical coil.

This natural tendency of the cord to form a helical coil may be furtherincreased by applying different tensions to the braided yarn. For

instance, in making a helical cord having a right hand pitch the tensionon the yarn from the series of cops l, which travel in acounterclockwise direction looking downwardly at the cops in Figure i,may be four ounces on each thread, while the tension on the yarn fromthe cops 8, which travel in a clockwise direction, may be eight ouncesper thread.

A cord made in this manner with the outer conductor of greater lengththan the inner conductors and the tension on the strands of the braidinggreater in one direction than in the other, will form a helicalextensible retractile coil without any other elastic materials. In somecases, however, it may be desirable to have elastic materials either asa part of the braided covering or in addition thereto. When usingelastic materials as a part of the braided covering, rubber strands orpreferably thread covered rubber strands of a type well known in the artmay be used on the cops 8 which travel in a clockwise direction and havethe higher tension applied thereto when making a retractile coil ofright hand pitch. If it is desired to make a coil of left hand pitch therelative tensions in the threads are reversed.

Fig. 6 illustrates a cord in which the threads drawn from the cops 8 areof an elastic matevrial such as rubber.

If it is desired to incorporate elastic material in the coil in additionto the braid, elastic strands ll are passed between tension rolls l8which are driven at a predetermined speed in relation to the capstan IE!to apply a tension of approximately 180% to the rubber strands. Theserubber strands are fed upwardly between the arms of the fork 13 of thecross piece l2 as shown in Figure 2.

It may be desirable in some cases to use an elastic member 2| whichpasses through the convolutions of the retractile coil and is attachedto the ends of the cord by the tips 22. This construction isparticularly useful when the cord embodies no other elastic materialsand relies for its elasticity on the construction which takes advantageof the inherent elasticity of the conductors and braiding material.

While particular tensions on the yarn and other specific embodimentshave been herein disclosed it will be evident that many changes andmodifications may be made therein without departing from the spirit'andscope of the invention.

What is claimed is:

1. A retractile electric cord comprising a plurality of helically coiledconductors, one of the conductors forming convolutions of greaterdiameter than another conductor, said conductors being substantiallyunstressed in the retracted state of the cord, and a fabric jacketcovering said conductors.

2. A retractile electric cord comprising a plurality of helically coiledconductors, one of the conductors having a longer length per convolutionthan another, said conductors being substantially unstressed in theretracted state of the cord, and a braided covering over said con--ductors.

3. A retractile electric cord comprising aplurality oi helically coiledconductors, one of the conductors forming convolutions of greaterperipheral length than another conductor said conductors beingsubstantially unstressed in the retracted state of the cord, a coveringof interbraided strands passing in opposite spirals around saidconductors, the tension in the strands going in one direction beinggreater than the tension in the strands going in the other direction.

l. A retractile electric cord comprising three conductors formed into ahelix, said conductors forming a triangle in cross-section with two ofthe conductors being of equal length, and the third conductor being of agreater length, said conductors being substantially unstressed in theretracted state of the cord, and a fabric covering said conductors.

5. A retractile electric cord comprising three conductors formed into ahelix, said conductors forming a triangle in cross-section with two ofthe conductors forming convolutions of equal peripheral length and thethird forming a convolution of greater length, said conductors beingcoiled conductor having a textile covering, and

substantially unstressed in the retracted state of v I thecord, acovering of interbraided strands over said conductors in which thestrands pass spirally in opposite directions around the conductors, the

strands going in one direction being under strands passing around theconductor in the opposite direction being relatively inelastic.

7. An electric cord comprising a helically coiled conductor having acovering of strands passing in opposite spirals around the conductor,the strands passing around the conductor in one direction being elasticand the strands passing around the conductorin the opposite directionbeing relatively inelastic. 8. A retractile electric cord comprising apluralityof helically coiled conductors, one of said conductors formingconvolutions of a greater peripheral length than another, saidconductors being substantially unstressed in the retracted state of thecord, and a. covering for said conductors of interbraided strandspassing in opposite spirals around the conductors, the strands passingin one. direction being elastic and the strands passing around theconductors in the opposite direction being relatively inelastic.

9. A retractile electric cord comprising a plurality of helically coiledconductors, one of said conductors being of greater length than anotherconductor, said conductors being substantially unstressed in theretracted state of the cord, a braided covering over said conductors,and elastic means tending to retain said cord in helically coiled form.

10. An electric cord comprising a plurality of helically coiledconductors, one of said conductors being of greater length than.another, and an elastic element attached to the ends oi" the cord andpassing through the convolutionsthereof in an axial direction.

11. A retractile electric cord comprising a plurality of conductors inhelically coiled form, one of said conductors being of greater lengththan another conductor, said conductors being substantially unstressedin the retracted state of the cord, a. covering of braided strandshaving strands passing in opposite spirals around the cord, the tensionin the spirals going in one direction being greater than the tension inthe strands going in the opposite direction, and an elastic elementattached to the ends of the cord and passing through the convolutions inan axial direction.

12. An electric cord comprising a helically conductor in the oppositedirection being relatively inelastic.

13. An electric cord comprising a helically an elastic element having anelasticity comparable to that of rubber spirally disposed around saidconductor so fixed relative to the conductor as to impart a torsionalforce which causes the cord to coil helically when unstressed.

14. An electric cord comprising a helically coiled conductor having acovering of braided strands and a stretchedrubber strand spirallydisposed around said conductor to cause the cord to coil helicallywhenunstressed.

15. An electric cord comprising a helically coiled conductor having acovering of interbraided strands and an elasticelement interbraided insaid covering and spirally disposed around said conductor to cause thecord to coil helically when unstressed. I

WILLIAM T. BARRANS. PAUL COLE.

